SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a37919b2019bcdaaf341d67529c9db76ca0912d4db6e7d5e5aa99a221ee589b5' 
  AND token = 'z5RM2jS8H/RLe3jbh7bZY5VWFWuJVclR3gbupGIEjaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}